The efficacy of x-ray doses on murine norovirus-1 (MNV-1) in pure culture, half-shell oyster, salmon sushi, and tuna salad

Authors: WU, Y - Mississippi State University; CHANG, S.K - Mississippi State University; NANNAPANENI, R - Mississippi State University; COKER, R - Mississippi State University; HAQUE, Z - Mississippi State University; MAHMOUD, B.S - Mississippi State University

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2015
Publication Date: 6/1/2016
Citation: Wu, Y.W., Chang, S.C., Nannapaneni, R., Coker, R., Haque, Z., Mahmoud, B.M. 2016. The efficacy of x-ray doses on murine norovirus-1 (MNV-1) in pure culture, half-shell oyster, salmon sushi, and tuna salad. Food Control. 64:77-80.

Interpretive Summary: Human norovirus (HuNoV) causes the most common foodborne illnesses in the United States. The CDC estimates 5,461,731 cases of illnesses, 14,663 hospitalizations and 149 deaths annually related to this pathogen. X-ray irradiation is a technology that can be used to inactivate pathogens and at the same time to retain food quality. To our knowledge, this is the first report of the inactivation of MNV-1 on seafood products by X-ray. The results of this study indicate that the efficacy of X-ray irradiation against MNV-1 increased with increasing X-ray doses. Based on the fact that X-ray machine is easy to operate without excessive labor requirement, X-ray could be a suitable nonthermal processing alternative to current disinfection techniques for seafood products.

Technical Abstract: n this investigation, we determined the efficacy of X-ray doses on reducing a human norovirus (HuNoV) surrogate [murine norovirus-1 (MNV-1)] in pure culture, half-shell oyster, salmon sushi and tuna salad. The pure culture (phosphate-buffer saline, pH 7.4), half-shell oyster, salmon sushi and tuna salad were inoculated with propagated MNV-1 virus stock solution. Half-shell oyster, tuna salad, and salmon sushi samples were then air-dried at 22 oC for 30 min and then packaged, separately, in sterilized bags prior to X-ray treatments. Samples were treated with 0.0, 1.0, 2.0, 3.0, 4.0 and 5.0 kGy X-ray. The results of plaque assays demonstrated a high susceptibility of MNV-1 to X-ray treatments. Treatments with 4.0 kGy X-ray achieved the reductions of 3.7 log PFU ml-1 in pure culture or 2.7, 2.2, and 2.0 log PFU g-1 in half-shell oyster, salmon sushi and tuna salad, respectively. Treatment with 5.0 kGy X-ray reduced the MNV-1 from, approximately, 5.5 to 2.9 log PFU g-1 in tuna salad or to below detection limit (<2.0 log PFU g-1) in half-shell oyster and salmon sushi. These results indicated that X-ray is a promising antiviral technology for the seafood industry.